Browsing by Keyword "Offshore wind energy"
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Item The Consequences of Air Density Variations over Northeastern Scotland for Offshore Wind Energy Potential(MDPI, 2019) Ulazia, Alain; Nafarrate, Ander; Ibarra-Berastegi, Gabriel; Sáenz, Jon; Carreno-Madinabeitia, SheilaHywind-Scotland is a wind farm in Scotland that for many reasons is at the leading edge of technology and is located at a paradigmatic study area for offshore wind energy assessment. The objective of this paper is to compute the Capacity Factor ( CF ) changes and instantaneous power generation changes due to seasonal and hourly fluctuations in air density. For that reason, the novel ERA5 reanalysis is used as a source of temperature, pressure, and wind speed data. Seasonal results for winter show that CF values increase by 3% due to low temperatures and denser air, with economical profit consequences of tens of thousands (US$). Hourly results show variations of 7% in air density and of 26% in power generation via FAST simulations, emphasizing the need to include air density in short-term wind energy studying.Item Seasonal Air Density Variations over The East of Scotland and The Consequences for Offshore Wind Energy(IEEE, 2018-12) Ulazia, Alain; Gonzalez-Roji, Santos J.; Ibarra-Berastegi, Gabriel; Carreno-Madinabeitia, Sheila; Saenz, Jon; Nafarrate, AnderIn this communication, offshore wind energy is studied around the East of Scotland, where, among other farms, the pioneering floating wind farm Hywind-Scotland is located. SIEMENS 160/6 turbines have been implemented in this farm, and we have thus used this turbine for our study. The main purpose is to compute the Capacity Factor (CF) changes due to air density variations in the study area. The impact of seasonal air density changes has been assessed as percentage reduction, but individual extreme cases have also been considered at Hywind-Scotland farm. Temperature, pressure, and wind speed data from the reanalysis ERA5 have been used for that. As a results, in winter, the CF increment due to low temperatures and denser air reaches values around 3% and summer-winter difference can reach the 4%, that is, 0.52 GWh of energy production for one SIEMENS 160/6.Item Seasonal Correction of Offshore Wind Energy Potential due to Air Density: Case of the Iberian Peninsula(MDPI AG, 2019) Ulazia, Alain; Ibarra-Berastegi, Gabriel; Sáenz, Jon; Carreno-Madinabeitia, Sheila; González-Rojí, Santos J.A constant value of air density based on its annual average value at a given location is commonly used for the computation of the annual energy production in wind industry. Thus, the correction required in the estimation of daily, monthly or seasonal wind energy production, due to the use of air density, is ordinarily omitted in existing literature. The general method, based on the implementation of the wind speed’s Weibull distribution over the power curve of the turbine, omits it if the power curve is not corrected according to the air density of the site. In this study, the seasonal variation of air density was shown to be highly relevant for the computation of offshore wind energy potential around the Iberian Peninsula. If the temperature, pressure, and moisture are taken into account, the wind power density and turbine capacity factor corrections derived from these variations are also significant. In order to demonstrate this, the advanced Weather Research and Forecasting mesoscale Model (WRF) using data assimilation was executed in the study area to obtain a spatial representation of these corrections. According to the results, the wind power density, estimated by taking into account the air density correction, exhibits a difference of 8% between summer and winter, compared with that estimated without the density correction. This implies that seasonal capacity factor estimation corrections of up to 1% in percentage points are necessary for wind turbines mainly for summer and winter, due to air density changes.